1. Field of the Invention
This invention generally relates to a cable adjustment device especially for a bicycle operating mechanism. More specifically, the present invention relates to cable adjustment device which allows for quick and easy adjustment of the effective length or tension of cable extending between a bicycle actuating mechanism (lever or shifting member) and a bicycle braking mechanism or derailleur.
2. Background Information
Bicycle control cables are interposed between actuating mechanisms, such as a brake lever or a shifter and its braking mechanism or derailleur. For example, when the brake lever is pulled, the inner wire of the control cable moves within the outer casing of the control cable to move the brake shoes from a disengaged position to a braking position in which the brake shoes engage the rim of the wheel. In the case of a derailleur, the shifter moves the inner wire of the control cable relative to the outer casing of the control cable such that the derailleur moves relative to the gears.
In particular, brake actuating mechanisms usually include a brake lever mounted to a base member for pivotal movement. The base member is typically mounted to a handlebar of a bicycle. A control cable extends from the braking mechanism to the brake lever. The brake lever pivots between a brake engagement position and a brake disengagement position. In the brake engagement position, the cable is pulled by the brake lever so that the cable moves brake shoes into engagement with corresponding bicycle tire rim to stop tire rotation of the tire. In the brake disengagement position, the cable tension is released and the braking mechanism is disengaged.
Typically, in the brake disengagement position, the brake lever and control cable are adjusted to allow the brake shoes to be spaced apart from the tire rim by only a small distance. This spacing can be adjusted by a threaded barrel adjustment which engages the outer casing of the control cable to change the effective length or tension of the cable between the barrel and the braking mechanism. Similarly, the shifter and control cable can be adjusted by a threaded barrel adjustment which engages the outer casing of the control cable to change the effective length or tension of the cable between the barrel and the shifter. The effective length or tension of the shift cable is adjusted to hold the chain on the correct sprocket or gear as well as to move the chain from gear to gear.
In the past, a locking nut was used to maintain the barrel adjustment to a particular setting. Often times, a tool was required to loosen the locking nut. More recently, various cable adjustment devices have been developed to maintain the barrel adjustment. These newer cable adjustment devices are often complex and/or expensive to manufacture. Some examples of cable adjustment devices are disclosed in U.S. Pat. Nos. 4,591,026 to Nagano; 4,833,937 to Nagano; and 5,674,142 to Jordan.
In view of the above, there exists a need for a cable adjustment device which is easily adjustable and inexpensive to manufacture. This invention addresses this need in the art as well as other needs in the art which will become apparent to those skilled in the art from this disclosure.